Rapidly disintegrating tablets are convenient delivery systems, which are designed to disintegrate rapidly upon contact with a fluid medium, which is typically an aqueous fluid medium. Orally disintegrating tablets are a class of rapidly disintegrating tablets, which are convenient oral delivery systems designed to disintegrate rapidly upon contact with aqueous fluids, e.g., water or saliva, to form a dispersion, which can be swallowed easily. Orally disintegrating tablets are particularly advantageous for patients, e.g., pediatric or aged patients, having difficulty swallowing conventional tablets or capsules, or for individuals who may not have difficulty swallowing, but may have an aversion to swallowing conventional tablets or capsules. Orally disintegrating tablets also are convenient under circumstances in which taking an oral dosage form with water may be inconvenient (e.g., while working or traveling).
Conventional rapidly disintegrating tablets are typically formed by compression (e.g., in a tablet press). It is desirable for such tablets to have sufficiently high hardness and sufficiently low friability to provide structural stability for transportation and storage. Low friability (which is measured based on the percent tablet weight loss after a certain number of revolutions in a friabilator) is desirable in that it is generally indicative of high tablet strength. High porosity of the tablet structure also is desirable in that it allows fluids (e.g., aqueous or bodily fluids, e.g., water or saliva) to be drawn or “wicked” from the external environment and into the interstices of the tablet structure, thereby promoting rapid and effective disintegration.
Rapidly disintegrating tablets have been described in U.S. Pat. No. 5,464,632 (Cousin et al.), which describes a tablet prepared by dry blending an active ingredient with a granulated carbohydrate, to form a composition, which is compressed, to form the tablet. Rapidly disintegrating tablets also have been described in U.S. Pat. No. 6,316,029 (Jain et al.), which describes a tablet prepared by compressing a blend of ingredients into a tablet. However, the process of forming the tablet described by Jain et al. requires relatively high compression forces (e.g., from 700 lbs. to 3800 lbs.). The high compression forces can result in a reduction in tablet porosity due to collapse of the void spaces during compression, thereby sacrificing the disintegration properties of the tablet.
As such, there exists a need for a conventional rapidly disintegrating tablet having sufficiently low friability and sufficiently high hardness, while maintaining high porosity of the tablet structure. The invention provides such a tablet. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.